MRI and CT in Traumatic Brain Injury - 2020 Annual Meeting | cspmrcspmr.com/beta/wp-content/uploads/2019/04/TBI-2019.pdf · 2019-04-29 · MRI and CT in Traumatic Brain Injury Diffusion

MRI and CT in Traumatic Brain Injury

Murray A. Solomon, M.D. InSight - Los Gatos MRI

MRI and CT in Traumatic Brain InjuryIs There Still a Roll for Plain X-Rays in the Evaluation of TBI

Patients?





CT Scanning in TBI Patients


Who Should Get a CT Scan?

Canadian CT Protocol

New Orleans CT Protocol

NICE UK CT Protocol

Neurosurgery Consensus 2017

+ 48 Hours

Bone Window


What Can You See with a CT Scan in TBI Patients ?

Skull Fractures

Brain Contusions

Acute Brain Hemorrhage

Extra-Axial Hemorrhage

Mass Effect/Midline Shift

Brain Herniations

Foreign Bodies

Skull Fractures with Associated Hemorrhage


Bone Window Soft Tissue Window


Soft Tissue Window


Soft Tissue Window Bone Window

Bone WindowSoft Tissue Window


MRI and CT in Traumatic Brain InjurySoft Tissue Window Bone Window

Epidural vs. Subdural Hematoma


Lentiform Crescentic

Skull Base Fractures



Bone Window

Bone Window

Diffuse Axonal Injury (DAI)

• Due to acceleration/deceleration of the white matter + hypoxia

• Patients have severe LOC at impact

• Grade 1: axonal damage in WM only - 67%

• Grade 2: WM + corpus callosum (posterior > anterior) - 21%

• Grade 3: WM + CC + brainstem - 12%


Diffuse Axonal Injury (DAI)

• Rarely detected on CT ( 20% of DAI lesions are hemorrhagic)

• MRI: T1, T2, DWI, T2 GRE, SWI



MRI in TBI Patients


MRI in TBI Patients

1983• T1W Images• PD/T2W Images

2019• T1W Images• PD/T2W Images• Diffusion Weighted

Images• T2 FLAIR Images• T1 FLAIR Images• GRE/SWI• DTI/FiberTracking• NeuroQuant• Arterial Spin Labeling• MR Angiography


What does MRI add to CT in TBI?


SWI

CT GE GE

Diffusion Weighted Imaging (DWI) in TBI


SWI vs. GRE

SW is 3-4x more sensitive than GRE for the detection of susceptibility

effects.


1.5 SWI 3T


38Y Male s/p Closed Head Trauma (Motorcycle Accident)

Insomnia, Altered Circadian Rhythms


T1 FLAIR T2W

3T MRI Images

T1 FLAIR T2W

3T MRI Images

T2W SWI

3T MRI Images

T2W SWI

3T MRI Images


3T DTI/FiberTracking in TBI

Why do we need DTI/FiberTracking?

Conventional MRI cannot reveal detailed anatomy of the white matter. On routine MRI scans the white matter looks homogeneous because it is homogeneous with respect to chemical composition (water concentration, T1 and T2 values). Diffusion Tensor Imaging (DTI) can generate contrasts that are sensitive to fiber orientation.


The diffusion of water molecules in biologic tissues can be measured using MR gradients and diffusion weighted

sequences. Water molecules are “tagged” with a very short gradient

pulse. The magnetization and phase of water molecules can measured and used

for localization and therefore the determination of diffusion.


Diffusion perpendicular to axon bundles is hindered by axonal cell membranes and myelin sheaths whereas it is unrestricted along them. Within axons, the diffusion of water will be greater parallel to the fibers.

When diffusion exhibits a preferential direction, it is termed anisotropic.

Fractional Anisotropy (FA) is a measure of the degree of anisotropy.


Courtesy of Tim Roberts & Mike Moseley

Anisotropic Diffusion in Celery

Fractional Anisotropy (FA)

A measure of the degree of anisotropy in a tensor model of diffusion at a given voxel. FA values are bounded between zero (a perfect sphere) and one (an infinitely long cigar shape)

Modeling Tracts from Seed Points

The “tracts” created with fiber tracking are mathematical analogs (stream tubules) of the WM tracts representing fractional anisotropy values and not actual WM fibers or bundles.

54Y F M.D. Anesthesiologist involved in a severe MVA with head trauma. She was airlifted by helicopter and

hospitalized at Stanford.


Mentation Changes after a Severe MVA

Severe MVA Age MatchedNormal

54YF Fell Down Stairs 1.5M Prior to MRI Scan. Hit Head “Hard” Several

Times Resulting in a Concussion

“Post-concussive Syndrome” with HA, Memory Loss, Difficulty with

Concentration

Severe MVA MRI and CT in Traumatic Brain Injury

Severe MVA MRI and CT in Traumatic Brain Injury

Normal

Patient

Corticospinal Tract (CST)

Corticospinal Tract (CST)

Left Corticospinal Tract

L R

Callosum Forceps Major

L R

Left Arcuate Fasiculus

Brain Segmentation

3T 3D Volume ImagingT1W 3D TFE with Sense

• TR 7

• TE 3.2

• 1.2mm sagittal slices, no gap

• 255 x 256 matrix

• Acquisition Time 9:13

• 180 slices (160 usable slices)

Pulse Sequence Chosen to Provide Thin Slices and Good GM-WM Discrimination

NeuroQuant Brain Volumetrics Reveals Significant Post-Traumatic Volume Loss of the Left Forebrain, Left Cortical Gray Matter, Left Hippocampus/Amygdala and Basal Ganglia on the Left Side.


Arterial Spin Labeling

ASL

What is ASL?

What is ASL?

ASL is an MRI method that enables the measurement of tissue perfusion (CBF) without the use of exogenous contrast agents by magnetically tagging (nulling the signal of) water in inflowing blood. Recent advances in pulse sequence design and the availability of 3T scanners have resulted in increased clinical adoption of ASL.

Cerebral Blood Flow (CBF) can be defined as the steady state delivery of blood to the tissue capillary bed. It is measured in ml/min/100g

1% Signal Difference Quantitative CBF

How Long Does It Take?

3T

1.5T

Acq time: 9 min.

Displaying ASL Data

Black and White

Colorized and Quantitative

Colorized Superimposed on T1W Images

Black and White Colorized/Quantitative Superimposed on T1W

Mr. XX Accident History

• Mr. XX is a 41YM, with a history of three prior concussions from which he completely recovered, who was involved in a motor vehicle accident suffering head trauma on 5/3/2017.

• Since the accident, Mr. XX has been experiencing memory difficulties including trouble with name recall, difficulty concentrating, and attention and focus impairment.

• Mr. XX’s symptoms are interfering with completing tasks and performance. He has been diagnosed with post concussive syndrome.

Mr. XX MRI of the Brain 3/7/19

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Asymmetric Decreased Cortical Perfusion Right Frontal Lobe



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Robert Thompson MRI of the Brain 3/7/19


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Quiz

What is the most sensitive sequence for

detecting postraumatic “microbleeds”?

What is the most sensitive sequence for

detecting postraumatic “microbleeds”?

Documents

MRI and CT in Traumatic Brain Injury - 2020 Annual Meeting | cspmrcspmr.com/beta/wp-content/uploads/2019/04/TBI-2019.pdf · 2019-04-29 · MRI and CT in Traumatic Brain Injury Diffusion